Siemens SINUMERIK 840Di Function Manual page 961

Signals NCK to PLC
The signals sent by the NCK to the PLC are divided into the following groups:
• Status signals from the NCK, channels, axes and spindles
• Modification signals of the auxiliary functions
• Values of the auxiliary functions
• Values of the G functions
Status signals:
The status signals from the NCK, channels, axes, and spindles are reset.
Auxiliary-function modification signals:
Auxiliary-function modification signals are also reset.
Auxiliary-function values:
Auxiliary-function values are retained so that it is possible to trace the last functions triggered
by the NCK.
G-function values:
G-function values are reset (i.e., initialized with the value 0).
PLC → NCK signals
The signals sent by the PLC to the NCK are divided into control signals and tasks that are
transferred by FCs to the NCK.
Control signals:
The control signals from the PLC to the NCK are frozen; cyclic updating by the basic
program is suspended.
Jobs from PLC to NCK:
The FCs and FBs, which are used to pass jobs to the NCK, must no longer be processed by
the PLC user program, as this could lead to incorrect checkback signals. During runup of the
control, a job (e.g., read NCK data) must not be activated in the user program until the NCK-
CPU ready signal is set.
Power Line Basic PLC Program (P3)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
2.7 Structure and functions of the basic program
Detailed description
2-49